1. Field of the Invention
The present invention relates, in general, to floorboards laid on the floor of a clean room where highly integrated circuit manufacturing, optical engineering, genetic engineering, space-air engineering or medical applications are processed and, more particularly, to a floorboard for such a clean room capable of improving the productivity of such processes, and being free from emitting disagreeable odors or toxic gases, and being usable for a lengthy period of time without being deformed.
2. Description of the Prior Art
As well known to those skilled in the art, it is necessary to keep the rooms where highly integrated circuit manufacturing, optical engineering, genetic engineering, space-air engineering or medical applications are processed clean so as to accomplish an optimal environment almost completely free from dust or bacteria. Such rooms have been so-called "clean rooms".
In order to maintain a desired cleanness of such clean rooms clean, the rooms individually have to be provided with an air conditioning system capable of forcibly circulating clean air in a room by introducing fresh air into the room and expelling existing room air, which may be contaminated with dust or bacteria, to the atmosphere.
Therefore, it is necessary to keep the floor of such a room clean. In order to accomplish such a clean state of the floor, specifically designed floorboards, having a high air ventilation effect, are laid on the floor. An example of typical floorboards for such clean rooms is shown in FIGS. 1 and 2. As shown in the drawings, the typical floorboard for clean rooms comprises a plate part 10 having a desired rectangular configuration. A latticed support part 11, having a predetermined height and a latticed bottom structure, is vertically and integrally formed on the lower surface of said plate part 10, thus supporting the plate part 10 when the floorboard is laid on the floor of a clean room. Provided on the upper surface of the plate part 10 is a tile 20. The tile 20, being smooth at its upper surface and having the same size and configuration as of the plate part 10, is attached to the upper surface of the plate part 10 through a bonding layer 30 which is formed at the junction between the tile 20 and the plate part 10 using a known bonding agent. As best seen in FIG. 2, the tile 20, attached to the plate part 10, is perforated on its top area at regularly and closely spaced positions through a drilling process, thus having a great number of ventilation holes 40. In such a case, the ventilation holes 40 are individually and completely formed on both the tile 20 and the plate part 10 from the top to the bottom. A tile holder (not shown), used for stably and firmly holding the tile 20 to the plate part 10, is provided at the edge of said plate part 10.
However, the above floorboard is problematic in that since the tile 20 is attached to the upper surface of the plate part 10 through the bonding layer 30, the floorboard undesirably emits disagreeable odors or toxic gases from the bonding agent of said bonding layer 30, and being harmful to human bodies. In addition, the bonding layer 30 fails to have a thermal and moisture stability due to the intrinsic characteristics of the bonding agent, so that the bonding strength of said layer 30 may vary in accordance with environmental temperature and humidity. This allows the tile 20 to undesirably slip on the plate part 10 when the atmospheric air has a high temperature and a high humidity during, for example, a summer season. Such a low thermal stability of the bonding layer 30 also allows said layer 30 to be exceedingly hardened at a low temperature, so that the bonding layer 30 may lose its desired bonding strength during, for example, a winter season. That is, the typical floorboard may fail to firmly integrate the tile 20 to the plate part 10 due to the intrinsic characteristics of the bonding layer 30, thus being easily deformed or damaged.
Another problem experienced in the above floorboard is caused in the process of manufacturing the floorboards. In order to produce such a floorboard, it is necessary to primarily and precisely cut the tile 20 so as to allow the tile 20 to be inserted into and held by the tile holder of the plate part 10 at its edges. Thereafter, a bonding agent is applied on either the upper surface of the plate part 10 or the lower surface of the tile 20, thus forming the bonding layer 30 prior to laying the tile 20 on the plate part 10. The tile 20 is, thereafter, pressed onto the plate part 10, thus being bonded to the upper surface of the plate part 10 and forming a floorboard. The floorboard is subjected to a drilling process where the floorboard is perforated at regularly and closely spaced positions so as to form the ventilation holes 40 individually extending from the upper surface of the tile 20 to the lower surface of the plate part 10. As described above, the process of manufacturing the known floorboard for clean rooms is very complex, consuming labor and time and reducing productivity and work efficiency while producing the floorboards.